import random

def random_char():
    ascii_code = list(range(ord('a'),ord('z')+1))+list(range(ord('A'),ord('Z')+1))
    index = random.randint(0,len(ascii_code)-1)
    code_num = ascii_code[index]
    return chr(code_num)

def random_string(length):
    s = ''
    for i in range(length):
        s += random_char()
    return s
